Typically this is a decoder issue on one of the displays affecting all of the other displays. If you disconnect all displays including credit/match and connect only the LED display does it still do it?

A problem with the Display Blanking signal can cause partial ghosting to adjacent digits.

I see you are mixing 6 digit displays with 7 digit displays and this might be your problem. The blanking signal on the 6 digit PCBs is connected to pins 10, 11 and 12, however on Stern 7 digit display PCBs, pin 11 is used for the millions digit and pin 12 is not connected.

The only position that should have a 6 digit display is the credit/ball in play display, so disconnect the 6 digit displays at player 2 and player 4 and see if the other three displays come up properly.

Also, it looks like you have a Bally 7 digit display at player 3? On Bally 7 digit displays, the millions digit signal is wired to pin 12 of the display connector, while on Stern 7 digit displays it's wired at pin 11.

Good catch Quench. I didn't notice the mix of 6 and 7 digit displays, that'll definitely cause problems.

Below quoted from my previous post: On the bottom of the Bally 7 digit display, connect the currently unused pin 11 to pin 12 of the pin header.